The disclosed technology relates generally to anti-slip strut tips, and particularly, to a surface-engaging “foot” assembly adapted to reduce lateral slipping between the foot and surface.
Axial forces applied from the strut to the foot assembly (and in turn to a surface) have a normal force component and a lateral force component. The normal force is perpendicular to the ground. The lateral force is parallel to the ground.
Unless the axial force from the strut is perfectly perpendicular to the surface, there will be a lateral component that will tend to cause the foot to slip along the surface. The force of friction between the foot assembly and the surface tends to resist slipping.
Many types of prior art feet fail to properly grip rugged terrain (including cracked surfaces, uneven sidewalks, pebbles and small obstacles, inclined surfaces, sand and gravel, and in various puddles of liquid). As a result, these prior art feet may not provide sufficient traction to counteract applied lateral forces, and the strut may slip.
Anti-slip features are desirable when the strut is a component of an ambulatory device, such as a cane, walker, crutch or forearm crutch. Anti-slip is particularly important for the forearm crutch. Typical users suffer from partial paralysis, cerebral palsy, or similar afflictions, and rely on the forearm crutch to support nearly all of their weight throughout the day. Since these devices are used to support significant portions of a user's bodyweight, any slipping between the device and environment can be devastating.
Such slipping can lead to the user's sudden loss of balance and stumbling, and may result in serious injury. Every year, an estimated 10,000 people suffer injuries—from broken bones to concussions—from falling during use of their forearm crutches.
There is a need for a foot assembly with improved gripping properties, especially on rugged terrain.